Related papers: Supersymmetric D-branes on SU(2) structure manifol…
In these lectures we start with a pedagogical introduction of the properties of open and closed superstrings and then, using the open/closed string duality, we construct the boundary state that provides the description of the maximally…
We construct two-dimensional N=(2,2) supersymmetric gauge theories with orthogonal and symplectic groups using branes and orientifold planes in Type IIA string theory. A number of puzzles regarding the construction, including the effect of…
In this thesis we elaborate on the three subjects of the title. We first show that supertubes exist and still preserve some supersymmetry in a large variety of curved backgrounds. Within the AdS/CFT correspondence we study the supersymmetry…
We construct the supergravity solution in 11 dimensions describing D6-branes wrapped around a Kahler four-cycle with a B-field along the flat directions of the brane. The configuration is dual to an N=2 noncommutative gauge theory in 2+1…
We develop a framework to construct worldvolume gauge theories on D2-branes probing compound Du Val (cDV) Calabi-Yau threefold singularities. By viewing these singularities as ADE surface fibrations over the complex $w$-plane, we encode…
We give the full lagrangean and supersymmetry transformation rules for D=5, N=2 supergravity interacting with an arbitrary number of vector, tensor and hyper-multiplets, with gauging of the R-symmetry group SU(2)_R as well as a subgroup K…
In the context of holography, we analyse aspects of supersymmetric geometries based on two-dimensional orbifolds known as spindles. By analysing spin$^c$ spinors on a spindle with an azimuthal rotation symmetry we show that under rather…
The $\mathscr{N}=2^*$ supersymmetric gauge theory is a massive deformation of $\mathscr{N}=4$, in which the adjoint hypermultiplet gets a mass. We present a D-brane realisation of the (non-)Abelian $\mathscr{N}=2^*$ theory, and compute…
We give an overview of D-branes in the maximally supersymmetric plane wave background of IIB supergravity. We start by reviewing the results of the probe analysis. We then present the open string analysis and show how certain spacetime…
We construct an explicit class of solutions of type IIB supergravity that is a smooth deformation of the 3-brane class of solutions. The solution is nonsupersymmetric and involves nontrivial dilaton and axion fields as well as the standard…
We study SL(3,R) deformations of a type IIB background based on D5 branes that is conjectured to be dual to N=1 SYM. We argue that this deformation of the geometry correspond to turning on a dipole deformation in the field theory on the D5…
Metastable, supersymmetry-breaking configurations can be created in flux geometries by placing antibranes in warped throats. Via gauge/gravity duality, such configurations should have an interpretation as supersymmetry-breaking states in…
We embed the large N Chern-Simons/topological string duality in ordinary superstrings. This corresponds to a large $N$ duality between generalized gauge systems with N=1 supersymmetry in 4 dimensions and superstrings propagating on…
A method of determining the mass spectrum of BPS D-branes in any phase limit of a gauged linear sigma model is introduced. A ring associated to monodromy is defined and one considers K-theory to be a module over this ring. A simple but…
We consider an infinite class of 5d supersymmetric gauge theories involving products of symplectic and unitary groups that arise from D4-branes at orbifold singularities in Type I' string theory. The theories are argued to be dual to warped…
We study the 6-dimensional N=2 supersymmetric grand unified theories with gauge group SU(N) and $ SO(M)$ on the extra space orbifolds $T^2/(Z_2)^3$ and $T^2/(Z_2)^4$, which can be broken down to the 4-dimensional N=1 supersymmetric…
Type IIB superstring models with the standard model gauge group on D3-branes and with massless matter associated with open strings joining D3-branes to D3-branes or D3-branes to ${\rm D}7_3$-branes are studied. Models with gauge coupling…
We construct D-branes in a left-right asymmetrically gauged WZW model, with the gauge subgroup embedded differently on the left and the right of the group element. The symmetry-preserving boundary conditions for the group-valued field $g$…
The world volume theory on N regular and M fractional D3-branes at the conifold singularity is a non-conformal n=1 supersymmetric SU(N+M) x SU(N) gauge theory. In previous work the Type IIB supergravity dual of this theory was constructed…
We consider D7-branes in the gauge theory/string theory correspondence, using a probe approximation. The D7-branes have four directions embedded holomorphically in a non-compact Calabi-Yau 3-fold (which for specificity we take to be the…